Transcript for Rogue Pilot Could Be Responsible For Missing Malaysian Plane

As we come on the air there are late breaking developments in the mystery of flight 370. Malaysia's prime minister making his first comments about the plane saying the investigation has now entered a, quote, new phase. According to the prime minister, the latest information confirms that whatever happened on board was adeliberate action. He said the aircraft communications systems were intentionally disabled which is why investigators are looking into whether this was a car hijacking on plane or a rogue pilot whose motivation remain unclear. Initially there was word the plane had been up in the air for four hours leaving search crews with a 2400-mile radius to search. Now it's up to eight hours expanding it to 4,000. Crews are concentrating are two corridors, first the border of Pakistan to northern Thailand, the southern the Indian ocean. A huge parameter. Earlier this morning in hi news conference we turn to ABC's David Kerley. Good morning. Reporter: Good morning, bianna. This does confirm our reporting which narrows the theories of what happened. It now appears it was taken over either by a rogue pilot or it was hijacked, as you mentioned and did stay in the air much longer than we thought. It's now clear say investigators communications gears switched off shall the changing direction of flight 370 appear to all be done on purpose by someone at the controls. This movement consistent with deliberate actions by someone on the plane. Reporter: This is the latest, a 12:41 departure from Kuala Lumpur to beijing but just past 26 minutes in, a data signaling system is shut off. Then 40 minutes in at 1:21 in the morning, the 777's location transmitter also shut off now confirmed, the plane does turn around heading back across Malaysia and is last seen on radar at 2:15 A.M. But this morning, we know because the jet was signaling a satellite each hour it turned again, either north or south and flew for another six hours at least. 3600 miles. A source and experts tell ABC news the southern route is the most likely uncovered by radar putting the Malaysian jet somewhere off Australia. Why and who did this? One unnamed Malaysian official is quoted as saying it's conclusive it's a hijacking. The prime minister, however, did not agree. Despite reports that the plane was hijacked, I wish to be very clear. We are sll investigating all possibilities as so what caused mh 370 to deviate from its original flight path. Reporter: And that includes the possibility that one or both of the pilots went rogue turning off that communications gear and turning around. We only know how far it flew because of the satellite pigs and we and the world's pilots only learned a couple of days ago that that system cannot be shut off by a pilot. So the search of the south China sea which is north of Malaysia has now been called off. No reason to look there. A new search will undoubtedly begin off Australia, but even though we know when the jet last pinged the satellite, it could have flown for another hour or so so there's still a bigger area to search, but not as big as what it could be. Dan? Huge area to search and this mystery just deepens. David Kerley, thank you for your continuing coverage. This new information gives new urgency, of course, to the investigation into the pilots. If fact, just hours ago they arrived at the home of the plane's captain and ABC's bob woodruff is in the Malaysian capital of Kuala Lumpur with the latest. Bob, good morning. Reporter: Well, good morning, Dan. You know, this news is just sweeping across this country of Malaysia right now. This has been going on for seven days now, the people have been criticizing the police for not searching through the homes of any of the pilots or crew members. Well, that's changing today. While search teams continue looking for the plane, the police here are trying to learn more about the crew members and passengers including the pilots. So far for the first time this week they searched the home of the pilot, captain zaharie Ahmad shah. ABC's Gloria Riviera was there at his gate watching the search. It was just after 2:42 when a white van came up to the Gates, was carrying two officers in plainclothes. Said they were from Malaysia's police headquarters after that a police car with two in uniforms came in spent two hours here. Upscale neighborhoods and neighbors say it's a tight-knit community. Reporter: In his home he has his own flight simulator. Also on the manifest is fariq Abdul Hamid, now engaged to be married. I visited his house yesterday. No one answered the door. Everyone I spoke to said nice things, especially this Malaysian singer, one of his closest friends. She grew up in the same hometown in panang. He is a nice guy, truly young. I don't think he's involved. Reporter: As the prime minister spoke today, family members watched it closely hoping for good news. This father's 29-year-old son is on that plane. His hope now is that he is still alive. One of the questions this morning is why did it take so much time for the government to reveal this kind of information? Well, it's been told by many people that if they did, people around the world have an idea where the plane may be and they can stench. They could look for any signs of it. Today the prime minister said that is the reason why they did finally release it today. Bianna? A lot of people probably saying that's not good enough. Thank you. Despite all the new information, there are still many unanswered questions about what happened on board flight 370. And for that we turn to ABC's Pierre Thomas who has more on the investigation and how it's proceeding from Washington. Pierre, good morning to you. Does it surprise you it took this long, eight days, for investigators to search the pilot's home? Did they waste valuable time? Reporter: Sources are saying they clearly do and the pilots would have been focus number one, something you needed to jump on early in the investigation and quite frankly this is the quandary that U.S. Law enforcement finds itself in. The FBI is not on the ground in Nevaeh and have no capacity to investigate. So what is us airways law enforcement going to encourage them to look at? Reporter: I expect them have them focus on the mental health of the piles and crew. They are the people that had easy access to the plane, control of the plane so they want to know was there something going on in their personal lives, mental health issues that needed to be resolved? That would be job number one. Reporter: The prime minister called it a deliberate act. What are your sources telling us? Reporter: So far they found nothing like that and one source pointed out a number. The plane had ample opportunity, the pilots were -- whoever was in control of that plane had ample opportunity to hit a populated area with a plane fuel of fuel so less concerned about that. On the other hand, they say the fact this plane was in the air so long and we still don't know where it is, huge problem. A huge mystery and, of course, ovr our thoughts and prayers with are the family and loved ones of those passengers, not knowing what happened. We appreciate your time this morning. Pierre. Dan? Let's bring in John nance who is a former commercial pilot and joins us from Seattle. John, good morning to you. We're now looking at a huge swath of the planet Earth that needs to be searched here. Even though they've narrowed it down to two corridors we're still talking about huge, huge sections to search. How can they begin to do this? You do this like eating an elephant. One bite at a time, in other words, you're going to have to basically decide what your search grid is and they're going to have to go at it just slice by slice by slice and the opportunity to be able to find this airplane, if it really is in the water, Dan, is very, very small. If it's in deep water in some points of the social several miles down even if they found it how would they retreat it? It's going to take a lot of special equipment. There's not all that much of it on the planet. You'll have to go down to 14 though thousand, 15,000, 16,000 feet and retrieving it will be quite a project akin to finding the "Titanic" and be able to bring some stuff up. First of all they'll have to locate it, a needle in the haystack. You have been in the aviation business for decades now. Does your gut tell you anything about what happened here? Yeah, with these supposed facts as long as they don't change about the sequence and the shutting off of radios and so on, did this is a hijack but probably an internal hijacking, in other words one of the pilots. It could be external but whoever was in control of the airplane after the turn knew what they were doing. They took it up to 45,000 feet. The chilling possibility there is it was for the purpose of killing the passengers. Killing possibility, indeed, and we keep saying this but it remains true, this is a mystery and an unprecedented one. John nance we really appreciate your guidance. Thank you.

This transcript has been automatically generated and may not be 100% accurate.

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